Monomer Emulsified Aqueous Ring-Opening Metathesis Polymerization (ME-ROMP) for the Synthesis of Water-Soluble Molecular Bottlebrushes with a Precise Structure
Wangmeng Hou, Yingqing Zhou, Xiuzhe Yin, Yongming Chen, Yi Shi
Abstract
Water-soluble molecular bottlebrushes (MBBs) with various functions and tunable morphologies have found promising application prospects in the biorelevant field. However, the facile synthesis of water-soluble MBBs with well-defined architectures is challenging by different chemistry. Herein, we explore the versatility of monomer emulsified aqueous ring-opening metathesis polymerization (ME-ROMP) for the facile synthesis of water-soluble MBBs via a grafting-through strategy. The grafting-through ME-ROMP was carried out by injecting a tiny amount of Grubbs’ third-generation catalyst (G3) solution of CH 2 Cl 2 into the aqueous solution of norbornene macromonomers (NB MMs) without deoxygenation, forming NB MMs-stabilized CH 2 Cl 2 /H 2 O emulsions. In this ME-ROMP, the NB moieties and G3 are concentrated in CH 2 Cl 2 droplets so that catalyst decomposition could be significantly suppressed and the steric hindrance of MMs reduced, leading to an accelerated polymerization. The results demonstrate that the ME-ROMP of NB MMs is living with ultrafast polymerization rates and near quantitative initiation and monomer conversion, producing well-defined water-soluble MBBs with diverse compositions and tunable contour lengths.